Persist column width preferences

[joelamb]

When columns are resized, the column widths are persisted to the preferences

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 26bf7bceac828cfe170746ccf00d9c13eebdeb22

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | -------------------- | ----- | | ember-headless-table | Minor |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions[bot]]

Preview URLs

GH Env: preview docs: https://360b5d5c.ember-headless-table.pages.dev api docs: https://360b5d5c.ember-headless-table.pages.dev/api/modules.html

[joelamb]

Conditionally approved~ish

my only concern is the arbitrary delay in test-support, as this could more than double the test time of every test wanting to resize columns.

Tests reliably pass with just a single 50ms delay between the drag and mouse up - but will not pass with a shorter delay (or no delay)